Özlem Aksoy

Morphological and anatomical contributions to the taxonomical identification of two Ornithogalum taxa (O. nutans and O. boucheanum) from Flora of Turkey

In this study, morphological and anatomical features of Ornithogalum nutans and O. boucheanum, two relative and morphologically similar species growing in European Turkey, were investigated. These species showed some important anatomical differences with regard to leaf anatomy while they have identical features in stem. The stem anatomy of these two species displays the common properties of monocotyledons. The mesophyll is unifacial and contains monotypic chlorenchyma cells in the leaf of O. nutans. It has no lacunae. The mesophyll in O. boucheanum is equifacial and it has lacunae. This anatomical distinction may be useful for the identification of these similar-looking species.

Investigation of mitosis, microsporogenesis and pollen germination in the critically endangered plant Amsonia orientalis (Apocynaceae)

Amsonia orientalis Decne. (Apocynaceae) is a medically useful and critically endangered plant which has very restricted distribution world-wide. The root tips and flower buds of A. orientalis were used as an experimental material and they were squashed in aceto-orcein. Fresh flowers and a liquid medium were used for pollen germination tests. In spite of the small size of the cells and chromosomes, all phases of mitosis and meiosis were observed. Generally the phases of mitosis were regular but there were a few abnormalities, such as laggard chromosome in metaphase and bridge formation in anaphase. There was a good relationship between the stages of pollen development and floral bud length. As a result of the cytokinesis, tetrahedral types of tetrads were occurred in microsporogenesis. The tetrad nuclei resulting from the simultaneous type of meiosis were found to be of equal size. Pollen germination had started from the first hour and pollen tube lengths and germination percentages regularly increased with increasing time. This is the first study that identifies mitotic and meiotic cycles and pollen germination in A. orientalis. Our findings about the mitosis and reproduction biology of this critically endangered plant will be useful for in vitro and in situ conservation, taxonomic and genetic studies.

The genotoxic effects of some food colorants on Zea mays L. var. saccharata Sturt

ABSTRACT Carmoisine and sunset yellow are organic azo dyes and widely used in food products, drugs and cosmetics. The present study was conducted to evaluate the toxic effects of these colorants on Zea mays with the root and shoot inhibition test, chlorophyll content, α-amylase activity and RAPD PCR technique. In the root inhibition test, EC50 values for carmoisine and sunset yellow were determined as 20 g l–1 and 22.5 g l–1, respectively. Chlorophyll a and chlorophyll b levels were decreased when compared to the control group for all of the carmoisine and sunset yellow concentrations. A slight increase was observed in enzyme activity in groups treated with 10 g l–1 and 20 g l–1 of carmoisine, while a decrease in enzyme activity was observed in the group treated with 40 g l–1 of carmoisine. For sunset yellow, a decrease in enzyme activity was observed in all concentrations. In the RAPD test, 71% polymorphism was obtained for carmoisine treated groups. Polymorphism ratio was determined as 53% for the group that was treated with sunset yellow. We concluded that both carmoisine and sunset yellow change the biochemical parameters and have genotoxic effects on Z. mays.

Investigation of the effects of quizalofop-P-ethyl on pollen germination of Hyacinthus orientalis L

Abstract Quizalofop-p-ethyl (QPE) is a phenoxy herbicide which is used in agriculture to control weeds. The cytotoxic effects of QPE on pollen germination and pollen tube group in Hyacinthus orientalis were investigated and compared to the control. Experiments were carried out different QPE concentrations (0.125 M and 0.25 M). It was found that in vitro pollen germination and tube growth of H. orientalis was affected by QPE treatments; in particular, the highest QPE concentration caused changes in the morphological features of H. orientalis. The most potent QPE reduced pollen germination by threefold. Morphological abnormalities in the pollen tube were also observed.